Of course, your friend or relative might be getting to that stage in life at which looking after themselves is becoming difficult. Perhaps they can’t walk as well as they used to and they’re prone to falling off or injuring themselves. Even if someone’s mind is still young and sharp, it can be very difficult to do simple things once the body deteriorates, so you need to be strong enough to help your loved one when they need it; even if they try to refuse your help. That might even involve moving in with them if they want or need that extra assistance.
As for mental deterioration, of course, you might struggle to take care of your friend or family member on your own.